Subframe availability for machine type communications (MTC)

ABSTRACT

Certain aspects of the present disclosure generally relate to wireless communications and more specifically to a method for machine type communications involving identifying one or more subframes, within at least one radio frame, unavailable for bundled transmissions across multiple subframes and communicating, via at least one narrowband region within a wider system bandwidth, using bundled transmissions across multiple subframes based on the identification.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application for patent is a continuation of U.S.Non-Provisional application Ser. No. 15/177,006, filed Jun. 8, 2016,which claims priority to U.S. Provisional Patent Application Ser. Nos.62/193,579, filed Jul. 16, 2015, 62/244,641, filed Oct. 21, 2015, and62/292,204, filed Feb. 5, 2016, each of which is assigned to theassignee of the present application and hereby expressly incorporated byreference herein in its entirety.

BACKGROUND I. Field of the Invention

Certain aspects of the present disclosure generally relate to wirelesscommunications and more specifically to systems utilizing devices withlimited communications resources, such as machine type communication(MTC) devices and enhanced MTC (eMTC) devices.

II. Description of Related Art

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, data, and so on. Thesesystems may be multiple-access systems capable of supportingcommunication with multiple users by sharing the available systemresources (e.g., bandwidth and transmit power). Examples of suchmultiple-access systems include code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, 3rd Generation PartnershipProject (3GPP) Long Term Evolution (LTE) including LTE-Advanced systemsand orthogonal frequency division multiple access (OFDMA) systems.

Generally, a wireless multiple-access communication system cansimultaneously support communication for multiple wireless terminals.Each terminal communicates with one or more base stations viatransmissions on the forward and reverse links. The forward link (ordownlink) refers to the communication link from the base stations to theterminals, and the reverse link (or uplink) refers to the communicationlink from the terminals to the base stations. This communication linkmay be established via a single-input single-output, multiple-inputsingle-output or a multiple-input multiple-output (MIMO) system.

A wireless communication network may include a number of base stationsthat can support communication for a number of wireless devices.Wireless devices may include user equipments (UEs). Some examples of UEsmay include cellular phones, smart phones, personal digital assistants(PDAs), wireless modems, handheld devices, navigation devices, gamingdevices, cameras, tablets, laptop computers, netbooks, smartbooks,ultrabooks, etc. Some UEs may be considered machine type communication(MTC) UEs, which may include remote devices, such as sensors, meters,monitors, location tags, drones, trackers, robots, etc., that maycommunicate with a base station, another remote device, or some otherentity. Machine type communications (MTC) may refer to communicationinvolving at least one remote device on at least one end of thecommunication and may include forms of data communication which involveone or more entities that do not necessarily need human interaction. MTCUEs may include UEs that are capable of MTC communications with MTCservers and/or other MTC devices through Public Land Mobile Networks(PLMN), for example.

To enhance coverage of certain devices, such as MTC devices, “bundling”may be utilized in which certain transmissions are sent as a bundle oftransmissions, for example, with the same information transmitted overmultiple subframes.

SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Certain aspects of the present disclosure provide a method for wirelesscommunications by a user equipment (UE). The method generally includesidentifying one or more subframes, within at least one radio frame,unavailable for bundled transmissions across multiple subframes andcommunicating, via at least one narrowband region within a wider systembandwidth, using bundled transmissions across multiple subframes basedon the identification.

Certain aspects of the present disclosure provide a method for wirelesscommunications by a user equipment (UE). The method generally includesdetermining a first set of subframes for valid downlink reception,determining a second set of subframes, determining a third set ofsubframes for valid downlink reception, based at least on the first setof subframes and the second set of subframes, receiving a downlinkchannel in the third set of subframes for valid downlink reception. Insome cases, determining the third set of subframes for valid downlinkreception comprises determining subframes which are contained in thefirst set of subframes for valid downlink reception and not contained inthe second set of subframes. Details of such determination are describedbelow.

Certain aspects of the present disclosure provide a method for wirelesscommunications by a user equipment (UE). The method generally includesdetermining a duplexing mode of a communication link, receiving systeminformation for the determined duplexing mode, and identifying subframesavailable for uplink and downlink transmission based at least on thereceived system information.

Numerous other aspects are provided including methods, apparatus,systems, computer program products, and processing systems.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 is a block diagram conceptually illustrating an example wirelesscommunication network, in accordance with certain aspects of the presentdisclosure.

FIG. 2 is a block diagram conceptually illustrating an example of anevolved nodeB (eNB) in communication with a user equipment (UE) in awireless communications network, in accordance with certain aspects ofthe present disclosure.

FIG. 3 is a block diagram conceptually illustrating an example framestructure for a particular radio access technology (RAT) for use in awireless communications network, in accordance with certain aspects ofthe present disclosure.

FIG. 4 illustrates example subframe formats for the downlink with anormal cyclic prefix, in accordance with certain aspects of the presentdisclosure.

FIGS. 5A and 5B illustrate an example of MTC co-existence within awideband system, such as LTE, in accordance with certain aspects of thepresent disclosure.

FIG. 6 illustrates an exemplary operation for wireless communicationsthat may be performed by a UE, in accordance with certain aspects of thepresent disclosure.

FIGS. 7-12 illustrate exemplary techniques for determining subframeavailability for bundled transmissions, in accordance with certainaspects of the present disclosure.

FIG. 13 illustrates an exemplary operation for wireless communicationsthat may be performed by a UE, in accordance with certain aspects of thepresent disclosure.

FIG. 14 illustrates an exemplary operation for wireless communications,in accordance with certain aspects of the present disclosure.

DETAILED DESCRIPTION

Aspects of the present disclosure provide techniques and apparatus fordetermining availability of subframes for bundled transmission. As willbe described in greater detail below, the availability (and how totransmit based on the availability) may be determined based on variousfactors, such as the reason subframes unavailable, reference (and/orsignaled) subframe configurations, and the type of channel subject tothe bundled transmission.

Accordingly, as will be described in more detail below, the techniquespresented herein may allow bundled uplink and downlink transmissions forcells with MTC devices.

The techniques described herein may be used for various wirelesscommunication networks such as Code Division Multiple Access (CDMA)networks, Time Division Multiple Access (TDMA) networks, FrequencyDivision Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA)networks, Single-Carrier FDMA (SC-FDMA) networks, etc. The terms“network” and “system” are often used interchangeably. A CDMA networkmay implement a radio technology such as Universal Terrestrial RadioAccess (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA), TimeDivision Synchronous CDMA (TD-SCDMA), and other variants of CDMA.cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network mayimplement a radio technology such as Global System for MobileCommunications (GSM). An OFDMA network may implement a radio technologysuch as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM®, etc. UTRA andE-UTRA are part of Universal Mobile Telecommunication System (UMTS).3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A), in bothfrequency division duplex (FDD) and time division duplex (TDD), are newreleases of UMTS that use E-UTRA, which employs OFDMA on the downlinkand SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM aredescribed in documents from an organization named “3rd GenerationPartnership Project” (3GPP). cdma2000 and UMB are described in documentsfrom an organization named “3rd Generation Partnership Project 2”(3GPP2). The techniques described herein may be used for the wirelessnetworks and radio technologies mentioned above as well as otherwireless networks and radio technologies. For clarity, certain aspectsof the techniques are described below for LTE/LTE-A, and LTE/LTE-Aterminology is used in much of the description below. LTE and LTE-A arereferred to generally as LTE.

FIG. 1 illustrates an example wireless communication network 100 withbase stations (BSs) and user equipments (UEs), in which aspects of thepresent disclosure may be practiced.

For example, one or more paging procedure enhancements for certain UEs(e.g., LC MTC UEs, LC eMTC UEs, etc.) in the wireless communicationnetwork 100 may be supported. According to the techniques presentedherein, the BSs and LC UE(s) in the wireless communication network 100may be able to determine, from the available system bandwidth supportedby the wireless communication network 100, which narrowband region(s)the LC UE(s) should monitor for a bundled paging message transmittedfrom the BSs in the wireless communication network 100. Also, accordingto techniques presented herein, the BSs and/or LC UE(s) in the wirelesscommunication network 100 may be able to determine and/or adapt thebundling size for the paging message based on one or more triggers inthe wireless communication network 100.

The wireless communication network 100 may be an LTE network or someother wireless network. Wireless communication network 100 may include anumber of evolved NodeBs (eNBs) 110 and other network entities. An eNBis an entity that communicates with user equipments (UEs) and may alsobe referred to as a base station, a Node B, an access point (AP), etc.Each eNB may provide communication coverage for a particular geographicarea. In 3GPP, the term “cell” can refer to a coverage area of an eNBand/or an eNB subsystem serving this coverage area, depending on thecontext in which the term is used.

An eNB may provide communication coverage for a macro cell, a pico cell,a femto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a closed subscriber group (CSG)). An eNB for a macro cell may bereferred to as a macro eNB. An eNB for a pico cell may be referred to asa pico eNB. An eNB for a femto cell may be referred to as a femto eNB ora home eNB (HeNB). In the example shown in FIG. 1, an eNB 110 a may be amacro eNB for a macro cell 102 a, an eNB 110 b may be a pico eNB for apico cell 102 b, and an eNB 110 c may be a femto eNB for a femto cell102 c. An eNB may support one or multiple (e.g., three) cells. The terms“eNB”, “base station,” and “cell” may be used interchangeably herein.

Wireless communication network 100 may also include relay stations. Arelay station is an entity that can receive a transmission of data froman upstream station (e.g., an eNB or a UE) and send a transmission ofthe data to a downstream station (e.g., a UE or an eNB). A relay stationmay also be a UE that can relay transmissions for other UEs. In theexample shown in FIG. 1, a relay (station) eNB 110 d may communicatewith macro eNB 110 a and a UE 120 d in order to facilitate communicationbetween eNB 110 a and UE 120 d. A relay station may also be referred toas a relay eNB, a relay base station, a relay, etc.

Wireless communication network 100 may be a heterogeneous network thatincludes eNBs of different types, e.g., macro eNBs, pico eNBs, femtoeNBs, relay eNBs, etc. These different types of eNBs may have differenttransmit power levels, different coverage areas, and different impact oninterference in wireless communication network 100. For example, macroeNBs may have a high transmit power level (e.g., 5 to 40 W) whereas picoeNBs, femto eNBs, and relay eNBs may have lower transmit power levels(e.g., 0.1 to 2 W).

A network controller 130 may couple to a set of eNBs and may providecoordination and control for these eNBs. Network controller 130 maycommunicate with the eNBs via a backhaul. The eNBs may also communicatewith one another, e.g., directly or indirectly via a wireless orwireline backhaul.

UEs 120 (e.g., 120 a, 120 b, 120 c) may be dispersed throughout wirelesscommunication network 100, and each UE may be stationary or mobile. A UEmay also be referred to as an access terminal, a terminal, a mobilestation (MS), a subscriber unit, a station (STA), etc. A UE may be acellular phone, a personal digital assistant (PDA), a wireless modem, awireless communication device, a handheld device, a laptop computer, acordless phone, a wireless local loop (WLL) station, a tablet, a smartphone, a netbook, a smartbook, an ultrabook, etc.

One or more UEs 120 in the wireless communication network 100 (e.g., anLTE network) may also be low cost (LC), low data rate devices, e.g.,such as LC MTC UEs, LC eMTC UEs, etc. The LC UEs may co-exist withlegacy and/or advanced UEs in the LTE network and may have one or morecapabilities that are limited when compared to the other UEs (e.g.,non-LC UEs) in the wireless network. For example, when compared tolegacy and/or advanced UEs in the LTE network, the LC UEs may operatewith one or more of the following: a reduction in maximum bandwidth(relative to legacy UEs), a single receive radio frequency (RF) chain,reduction of peak rate, reduction of transmit power, rank 1transmission, half duplex operation, etc. As used herein, devices withlimited communication resources, such as MTC devices, eMTC devices, etc.are referred to generally as LC UEs. Similarly, legacy devices, such aslegacy and/or advanced UEs (e.g., in LTE) are referred to generally asnon-LC UEs.

FIG. 2 is a block diagram of a design of BS/eNB 110 and UE 120, whichmay be one of the BSs/eNBs 110 and one of the UEs 120, respectively, inFIG. 1. BS 110 may be equipped with T antennas 234 a through 234 t, andUE 120 may be equipped with R antennas 252 a through 252 r, where ingeneral T≥1 and R≥1.

At BS 110, a transmit processor 220 may receive data from a data source212 for one or more UEs, select one or more modulation and codingschemes (MCSs) for each UE based on channel quality indicators (CQIs)received from the UE, process (e.g., encode and modulate) the data foreach UE based on the MCS(s) selected for the UE, and provide datasymbols for all UEs. Transmit processor 220 may also process systeminformation (e.g., for semi-static resource partitioning information(SRPI), etc.) and control information (e.g., CQI requests, grants, upperlayer signaling, etc.) and provide overhead symbols and control symbols.Processor 220 may also generate reference symbols for reference signals(e.g., the common reference signal (CRS)) and synchronization signals(e.g., the primary synchronization signal (PSS) and secondarysynchronization signal (SSS)). A transmit (TX) multiple-inputmultiple-output (MIMO) processor 230 may perform spatial processing(e.g., precoding) on the data symbols, the control symbols, the overheadsymbols, and/or the reference symbols, if applicable, and may provide Toutput symbol streams to T modulators (MODs) 232 a through 232 t. EachMOD 232 may process a respective output symbol stream (e.g., for OFDM,etc.) to obtain an output sample stream. Each MOD 232 may furtherprocess (e.g., convert to analog, amplify, filter, and upconvert) theoutput sample stream to obtain a downlink signal. T downlink signalsfrom modulators 232 a through 232 t may be transmitted via T antennas234 a through 234 t, respectively.

At UE 120, antennas 252 a through 252 r may receive the downlink signalsfrom BS 110 and/or other BSs and may provide received signals todemodulators (DEMODs) 254 a through 254 r, respectively. Each DEMOD 254may condition (e.g., filter, amplify, downconvert, and digitize) itsreceived signal to obtain input samples. Each DEMOD 254 may furtherprocess the input samples (e.g., for OFDM, etc.) to obtain receivedsymbols. A MIMO detector 256 may obtain received symbols from all Rdemodulators 254 a through 254 r, perform MIMO detection on the receivedsymbols if applicable, and provide detected symbols. A receive processor258 may process (e.g., demodulate and decode) the detected symbols,provide decoded data for UE 120 to a data sink 260, and provide decodedcontrol information and system information to a controller/processor280. A channel processor may determine reference signal received power(RSRP), received signal strength indicator (RSSI), reference signalreceived quality (RSRQ), CQI, etc.

On the uplink, at UE 120, a transmit processor 264 may receive andprocess data from a data source 262 and control information (e.g., forreports comprising RSRP, RSSI, RSRQ, CQI, etc.) fromcontroller/processor 280. Processor 264 may also generate referencesymbols for one or more reference signals. The symbols from transmitprocessor 264 may be precoded by a TX MIMO processor 266 if applicable,further processed by MODs 254 a through 254 r (e.g., for SC-FDM, OFDM,etc.), and transmitted to BS 110. At BS 110, the uplink signals from UE120 and other UEs may be received by antennas 234, processed by DEMODs232, detected by a MIMO detector 236 if applicable, and furtherprocessed by a receive processor 238 to obtain decoded data and controlinformation sent by UE 120. Processor 238 may provide the decoded datato a data sink 239 and the decoded control information tocontroller/processor 240. BS 110 may include communication unit 244 andcommunicate to network controller 130 via communication unit 244.Network controller 130 may include communication unit 294,controller/processor 290, and memory 292.

Controllers/processors 240 and 280 may direct the operation at BS 110and UE 120, respectively. For example, controller/processor 240 and/orother processors and modules at BS 110 may perform or direct operationsillustrated in FIGS. 7 and 11 and/or other processes for the techniquesdescribed herein. Similarly, controller/processor 280 and/or otherprocessors and modules at UE 120 may perform or direct operationsillustrated in FIGS. 8 and 12 and/or processes for the techniquesdescribed herein. Memories 242 and 282 may store data and program codesfor BS 110 and UE 120, respectively. A scheduler 246 may schedule UEsfor data transmission on the downlink and/or uplink.

FIG. 3 shows an exemplary frame structure 300 for FDD in LTE. Thetransmission timeline for each of the downlink and uplink may bepartitioned into units of radio frames. Each radio frame may have apredetermined duration (e.g., 10 milliseconds (ms)) and may bepartitioned into 10 subframes with indices of 0 through 9. Each subframemay include two slots. Each radio frame may thus include 20 slots withindices of 0 through 19. Each slot may include L symbol periods, e.g.,seven symbol periods for a normal cyclic prefix (as shown in FIG. 2) orsix symbol periods for an extended cyclic prefix. The 2L symbol periodsin each subframe may be assigned indices of 0 through 2L−1.

In LTE, an eNB may transmit a primary synchronization signal (PSS) and asecondary synchronization signal (SSS) on the downlink in the center1.08 MHz of the system bandwidth for each cell supported by the eNB. ThePSS and SSS may be transmitted in symbol periods 6 and 5, respectively,in subframes 0 and 5 of each radio frame with the normal cyclic prefix,as shown in FIG. 3. The PSS and SSS may be used by UEs for cell searchand acquisition. The eNB may transmit a cell-specific reference signal(CRS) across the system bandwidth for each cell supported by the eNB.The CRS may be transmitted in certain symbol periods of each subframeand may be used by the UEs to perform channel estimation, channelquality measurement, and/or other functions. The eNB may also transmit aphysical broadcast channel (PBCH) in symbol periods 0 to 3 in slot 1 ofcertain radio frames. The PBCH may carry some system information. TheeNB may transmit other system information such as system informationblocks (SIBs) on a physical downlink shared channel (PDSCH) in certainsubframes. The eNB may transmit control information/data on a physicaldownlink control channel (PDCCH) in the first B symbol periods of asubframe, where B may be configurable for each subframe. The eNB maytransmit traffic data and/or other data on the PDSCH in the remainingsymbol periods of each subframe.

The PSS, SSS, CRS, and PBCH in LTE are described in 3GPP TS 36.211,entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); PhysicalChannels and Modulation,” which is publicly available.

FIG. 4 shows two example subframe formats 410 and 420 for the downlinkwith a normal cyclic prefix. The available time frequency resources forthe downlink may be partitioned into resource blocks. Each resourceblock may cover 12 subcarriers in one slot and may include a number ofresource elements. Each resource element may cover one subcarrier in onesymbol period and may be used to send one modulation symbol, which maybe a real or complex value.

Subframe format 410 may be used for an eNB equipped with two antennas. ACRS may be transmitted from antennas 0 and 1 in symbol periods 0, 4, 7,and 11. A reference signal is a signal that is known a priori by atransmitter and a receiver and may also be referred to as pilot. A CRSis a reference signal that is specific for a cell, e.g., generated basedon a cell identity (ID). In FIG. 4, for a given resource element withlabel Ra, a modulation symbol may be transmitted on that resourceelement from antenna a, and no modulation symbols may be transmitted onthat resource element from other antennas. Subframe format 420 may beused for an eNB equipped with four antennas. A CRS may be transmittedfrom antennas 0 and 1 in symbol periods 0, 4, 7, and 11 and fromantennas 2 and 3 in symbol periods 1 and 8. For both subframe formats410 and 420, a CRS may be transmitted on evenly spaced subcarriers,which may be determined based on cell ID. Different eNBs may transmittheir CRSs on the same or different subcarriers, depending on their cellIDs. For both subframe formats 410 and 420, resource elements not usedfor the CRS may be used to transmit data (e.g., traffic data, controldata, and/or other data).

An interlace structure may be used for each of the downlink and uplinkfor FDD in LTE. For example, Q interlaces with indices of 0 through Q−1may be defined, where Q may be equal to 4, 6, 8, 10, or some othervalue. Each interlace may include subframes that are spaced apart by Qframes. In particular, interlace q may include subframes q, q+Q, q+2Q,etc., where q∈{0, . . . , Q−1}.

The wireless network may support hybrid automatic retransmission request(HARQ) for data transmission on the downlink and uplink. For HARQ, atransmitter (e.g., an eNB 110) may send one or more transmissions of apacket until the packet is decoded correctly by a receiver (e.g., a UE120) or some other termination condition is encountered. For synchronousHARQ, all transmissions of the packet may be sent in subframes of asingle interlace. For asynchronous HARQ, each transmission of the packetmay be sent in any subframe.

A UE may be located within the coverage of multiple eNBs. One of theseeNBs may be selected to serve the UE. The serving eNB may be selectedbased on various criteria such as received signal strength, receivedsignal quality, path loss, etc. Received signal quality may bequantified by a signal-to-interference-plus-noise ratio (SINR), or areference signal received quality (RSRQ), or some other metric. The UEmay operate in a dominant interference scenario in which the UE mayobserve high interference from one or more interfering eNBs.

As mentioned above, one or more UEs in the wireless communicationnetwork (e.g., wireless communication network 100) may be devices thathave limited communication resources, such as LC UEs, as compared toother (non-LC) devices in the wireless communication network.

In some systems, for example, in LTE Rel-13, the LC UE may be limited toa particular narrowband assignment (e.g., of no more than six resourceblocks (RBs)) within the available system bandwidth. However, the LC UEmay be able to re-tune (e.g., operate and/or camp) to differentnarrowband regions within the available system bandwidth of the LTEsystem, for example, in order to co-exist within the LTE system.

As another example of coexistence within the LTE system, LC UEs may beable to receive (with repetition) legacy physical broadcast channel(PBCH) (e.g., the LTE physical channel that, in general, carriesparameters that may be used for initial access to the cell) and supportone or more legacy physical random access channel (PRACH) formats. Forexample, the LC UE may be able to receive the legacy PBCH with one ormore additional repetitions of the PBCH across multiple subframes. Asanother example, the LC UE may be able to transmit one or morerepetitions of PRACH (e.g., with one or more PRACH formats supported) toan eNB in the LTE system. The PRACH may be used to identify the LC UE.Also, the number of repeated PRACH attempts may be configured by theeNB.

The LC UE may also be a link budget limited device and may operate indifferent modes of operation (e.g. entailing different amounts ofrepeated messages transmitted to or from the LC UE) based on its linkbudget limitation. For example, in some cases, the LC UE may operate ina normal coverage mode in which there is little to no repetition (e.g.,the amount of repetition needed for the UE to successfully receiveand/or transmit a message may be low or repetition may not even beneeded). Alternatively, in some cases, the LC UE may operate in acoverage enhancement (CE) mode in which there may be high amounts ofrepetition. In some cases, a determination may be made as to whether ornot the UE is in a coverage enhancement (CE) mode and transmission maybe adjusted based on the determination. For example, for a 328 bitpayload, a LC UE in CE mode may need 150 or more repetitions of thepayload in order to successfully receive the payload.

In some cases, e.g., also for LTE Rel-13, the LC UE may have limitedcapabilities with respect to its reception of broadcast and unicasttransmissions. For example, the maximum transport block (TB) size for abroadcast transmission received by the LC UE may be limited to 1000bits. Additionally, in some cases, the LC UE may not be able to receivemore than one unicast TB in a subframe. In some cases (e.g., for boththe CE mode and normal mode described above), the LC UE may not be ableto receive more than one broadcast TB in a subframe. Further, in somecases, the LC UE may not be able to receive both a unicast TB and abroadcast TB in a subframe.

For MTC, LC UEs that co-exist in the LTE system may also support newmessages for certain procedures, such as paging, random accessprocedure, etc. (e.g., as opposed to conventional messages used in LTEfor these procedures). In other words, these new messages for paging,random access procedure, etc. may be separate from the messages used forsimilar procedures associated with non-LC UEs. For example, as comparedto conventional paging messages used in LTE, LC UEs may be able tomonitor and/or receive paging messages that non-LC UEs may not be ableto monitor and/or receive. Similarly, as compared to conventional randomaccess response (RAR) messages used in a conventional random accessprocedure, LC UEs may be able to receive RAR messages that also may notbe able to be received by non-LC UEs. The new paging and RAR messagesassociated with LC UEs may also be repeated one or more times (e.g.,“bundled”). In addition, different numbers of repetitions (e.g.,different bundling sizes) for the new messages may be supported.

Example MTC Coexistence within a Wideband System

As mentioned above, MTC and/or eMTC operation may be supported in thewireless communication network (e.g., in coexistence with LTE or someother RAT). FIGS. 5A and 5B, for example, illustrate an example of howLC UEs in MTC operation may co-exist within a wideband system, such asLTE.

As illustrated in the example frame structure of FIG. 5A, subframesassociated with MTC and/or eMTC operation may be time divisionmultiplexed (TDM) with regular subframes associated with LTE (or someother RAT).

Additionally or alternatively, as illustrated in the example framestructure of FIG. 5B, one or more narrowband regions used by LC UEs inMTC may be frequency division multiplexed within the wider bandwidthsupported by LTE. Multiple narrowband regions, with each narrowbandregion spanning a bandwidth that is no greater than a total of 6 RBs,may be supported for MTC and/or eMTC operation. In some cases, each LCUE in MTC operation may operate within one narrowband region (e.g., at1.4 MHz or 6 RBs) at a time. However, LC UEs in MTC operation, at anygiven time, may re-tune to other narrowband regions in the wider systembandwidth. In some examples, multiple LC UEs may be served by the samenarrowband region. In other examples, multiple LC UEs may be served bydifferent narrowband regions (e.g., with each narrowband region spanning6 RBs). In yet other examples, different combinations of LC UEs may beserved by one or more same narrowband regions and/or one or moredifferent narrowband regions.

The LC UEs may operate (e.g., monitor/receive/transmit) within thenarrowband regions for various different operations. For example, asshown in FIG. 5B, a first narrowband region (e.g., spanning no more than6 RBs of the wideband data) of a subframe may be monitored by one ormore LC UEs for either a PSS, SSS, PBCH, MTC signaling, or pagingtransmission from a BS in the wireless communication network. As alsoshown in FIG. 5B, a second narrowband region (e.g., also spanning nomore than 6 RBs of the wideband data) of a subframe may be used by LCUEs to transmit a RACH or data previously configured in signalingreceived from a BS. In some cases, the second narrowband region may beutilized by the same LC UEs that utilized the first narrowband region(e.g., the LC UEs may have re-tuned to the second narrowband region totransmit after monitoring in the first narrowband region). In some cases(although not shown), the second narrowband region may be utilized bydifferent LC UEs than the LC UEs that utilized the first narrowbandregion.

Although the examples described herein assume a narrowband of 6 RBs,those skilled in the art will recognize that the techniques presentedherein may also be applied to different sizes of narrowband regions.

Example Subframe Availability for eMTC UEs

As mentioned above, LC MTC UEs were introduced in LTE Rel-12. Additionalenhancements may be made in LTE Release 13 (Rel-13) to support MTCoperations. For example, MTC UEs may be able to operate (e.g., monitor,transmit, and receive) in a narrowband region of 1.4 MHz or six RBswithin wider system bandwidths (e.g., 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15MHz, 20 MHz). As a second example, base stations and MTC UEs may supportcoverage enhancements (CE) of up to 15 dB by some techniques, forexample bundling. Coverage enhancement may also be referred to ascoverage extension and range extension.

Other enhancements that may be made in LTE Rel-13 may include basestations transmitting paging signals in MTC physical downlink controlchannels (MPDCCHs) in a narrowband in order to page MTC UEs. An MPDCCHmay convey paging signals for multiple MTC UEs and a downlink controlinformation (DCI) to one or more other MTC UEs. MPDCCH may be similar toPDCCH/EPDCCH as described above. Demodulation reference signal (DMRS)based demodulation may be supported when using MPDCCH. That is, a BStransmitting an MPDCCH may transmit DMRS with the MPDCCH. A UE receivingthe MPDCCH and DMRS may demodulate the MPDCCH based on the DMRS.

In order to achieve coverage enhancement (e.g. 15 dB CE), transmissionsmay be bundled (repeated) many times, for example, across multiplesubframes. FIG. 7 illustrates an example 710 of bundling with a bundle(repetition) size of 6 (for uplink or downlink). One challenge whenperforming bundling, however, is that not all subframes are availablefor repetition. For example, a TDD subframe configuration may indicatecertain subframes as DL, meaning they are not available for bundled ULtransmissions or may indicate certain subframes as UL, meaning they arenot available for bundled DL transmissions. In addition, certainsubframes may be designated for other purposes, such asMulticast-broadcast single-frequency network (MBSFN) or enhanced MBSFN(eMBSFN) or for use as measurement gaps (e.g., for a UE to tune-away andtake measurements on other frequencies).

In any case, aspects of the present disclosure provide techniques foraddressing the fact that certain subframes may not be available foruplink and/or downlink bundled transmissions.

FIG. 6 illustrates example operations 600 for wireless communicationsthat may be performed by a UE (e.g., UE 120 a in FIG. 1), such as an MTCUE.

Operation 600 begins at block 602, with the UE identifying one or moresubframes, within at least one radio frame, unavailable for bundledtransmissions across multiple subframes. At 604, the UE communicates,via at least one narrowband region within a wider system bandwidth,using bundled transmissions across multiple subframes based on theidentification. As described herein, the communicating may be adjustedbased on the classification of unavailable subframes (techniques ofclassifying are described herein). In some cases, communicating may beadjusted to skip bundled transmissions that would occur on one or moreunavailable subframes of the second group to one or more later occurring(subsequent) subframes or to postpone bundled transmissions if they arescheduled to occur on one or more unavailable subframes of the firstgroup and to schedule the postponed bundled transmissions to one or morelater occurring subframes.

There are various options for exactly how a UE performs bundledtransmissions given the unavailability of certain subframes, that wouldotherwise be scheduled for bundled transmissions. For example, referringagain, to FIG. 7, unavailable subframes may be postponed, as shown inexample 720, where transmissions that would have been transmitted onunavailable subframes SF1 and SF2 are postponed to SF6 and SF7. Asanother example, subframes may be skipped, as shown in example 730,where transmissions that would have been transmitted on unavailablesubframes SF1 and SF2 are skipped altogether.

In some cases, how unavailable subframes are treated may depend on whythey are unavailable. For example, subframes not available may beclassified into two groups. A first group (Group 1) may includesubframes not available to any eMTC UE (e.g., due to MBSFN or TDD).Group 1 subframes are typically signaled in broadcast transmissions(e.g., SIB). A second group (Group 2) may include subframes notavailable to a particular UE (e.g., because of a collision withmeasurement gap). Group 2 subframes are typically signaled in a per-UEbasis (e.g. RRC). As illustrated in FIG. 8, which shows an example witha bundling size of 10, subframes of Group 1 may be postponed, whilesubframes in Group 2 may be skipped (resulting in an effective bundlingsize less than 10).

In some cases, TDD subframe configurations may be dynamically updatedfor example, based on enhanced Interference Mitigation and TrafficAdaptation (eIMTA) schemes. This may present challenges for eMTC UEstrying to determine availability of subframes for bundled transmissions.Dynamic TDD configurations are typical signaled in PDCCH common searchspace.

Unfortunately, eMTC UEs may not be able to track the TDD configurationchanges because of being narrowband or in coverage enhancement. Further,signaling eIMTA configurations to eMTC UEs may be costly (repeating inmany narrowbands) or not possible (bundle size for M-PDCCH is longerthan eIMTA update period). Using a default TDD configuration may notwork in general for bundled uplink and downlink transmission. Forexample, as illustrated in FIG. 9, in a cell with eIMTA switchingbetween configurations 1 and 2, UL bundled transmissions (on SF3 andSF7) by a UE using configuration 1 would collide with DL transmissions(also on SF3 and SF7) if the cell is using configuration 2. In anotherexample, DL bundled transmissions (on SF3 and SF7) by a UE usingconfiguration 2 would collide with UL transmissions (also on SF3 andSF7) if the cell is using configuration 1.

One approach to address dynamically signal SF configurations, such as ineIMTA, is to configure a UE with some subframes for uplink and some fordownlink. As illustrated in FIG. 10, the signaling may be provided via abitmap indicating subframe availability. The top diagram in FIG. 10illustrates the actual UL/DL subframe configurations seen by “legacy”eIMTA UEs, while the bottom diagram illustrates the availability ofUL/DL subframes for bundled transmissions based on the bitmaps. It ispossible to also include information on subframe availability notrelated to TDD, e.g. MBSFN subframes or subframes that the eNB want toreserve for legacy users.

Another option is to configure eMTC UEs with one TDD subframeconfiguration for uplink and a different one for downlink. For example,a UE may use configuration 1 for downlink and configuration 2 for uplink(effectively avoiding collisions). In some cases, an MTC UE may reusecertain same fields as legacy UE (e.g., that may have to be transmittedon eMTC SIB). For example, these may include TDD Configuration from SIB1used for DL subframes or HARQ-ReferenceConfig (eIMTA configuration) usedfor U subframes.

In some cases, if an LTE eMTC uplink subframes are (explicitly)scheduled, a UE may just follow the downlink grant. In some cases, forUE without coverage enhancement (no bundling—or with small coverageenhancement), the UE follow an uplink grant. As an example, if a grantis received for subframe M then the UE may transmit uplink on subframe Mregardless of the TDD (or HARQ-ReferenceConfig) configuration.

For a UE in coverage enhancement, bundling may be needed for both uplinkand downlink, so the available uplink subframes may be given byHARQ-ReferenceConfig or a similar field. In some cases, for a UE thatdoes not need MPDCCH bundled but bundled PUSCH, for a current radioframe, the UE may use the scheduled subframe plus subframes indicated ina HARQ-ReferenceConfig. For other radio frames (e.g., if bundling sizeis long) the UE may only use subframes indicated as available forbundling via HARQ-ReferenceConfig. This approach may be useful for smalluplink bundle size (e.g. 2). In some cases, a UE may simply use thebroadcast (SIB) configuration, if a certain configuration is broadcast(e.g., cfg #0). Otherwise, the UE may use another (reference)configuration.

FIG. 11 illustrates an example where the SIB broadcast configuration isConfiguration 3, while the HARQ-ReferenceConfig is Configuration 4. Inthe illustrated scenario, if an (explicit) grant is received for asubframe whose availability is unknown (the subframe marked as “?”), theUE may assume that is an UL subframe and, at least for this radio frame,use that subframe for a bundled UL transmission. On the other hand, inthe example illustrated in FIG. 12, when a subframe availability isunknown the UE may avoid this subframe absent an explicit grant.

In some cases, a UE may determine subframe availability differently fordifferent channels (e.g., mPDCCH and PDSCH scheduled mPDCCH, BroadcastPDSCH vs. unicast PDSCH, or mPDCCH based PDSCH vs. mPDCCH-less PDSCH).One possible example is that for unicast PDSCH, subframe availabilitymay be somehow indicated in DCI itself, albeit with limited information.For example, an eNB may configure a reference configuration for mPDCCH,broadcast PDSCH, and mPDCCH-less PDSCH. The eNB may separately configurea reference configuration for unicast mPDCCH-based PDSCH (e.g., for noor low coverage enhancement cases). For example, two configurations maybe signaled in SIB1, and a bit in DCI may be used to switch betweenthese two. Such a mode may be enabled in a per-UE basis (e.g. RRCconfiguration).

In some cases, special subframe configurations may be signaledseparately to legacy UEs and eMTC UEs. For example, the update periodfor system information (SI) carrying subframe configuration informationmay be different for eMTC and regular UEs. This may also imply that thatDMRS configuration may be different for both types of UE. In such cases,it might not be possible to multiplex legacy UE and LC UE in the same RBfor MPDCCH/PDCCH for special subframes. In some cases, the UE receivesSI updates regarding subframe configurations with a differentperiodicity than UEs that do not communicate via the narrowband region.

In some cases, subframe availability may be signaled for deployments ofdifferent duplexing modes. For example, FIG. 13 illustrates exampleoperations 1300 that may be performed by a UE to receive signaling ofsubframe availability in TDD and FDD deployments.

The operations 1300 begin, at 1302, by determining a duplexing mode of acommunication link. At 1304, the UE receives system information for thedetermined duplexing mode. At 1306, the UE identifies subframesavailable for uplink and downlink transmission based at least on thereceived system information.

This subframe availability may account for various types of subframeconfigurations, such as dynamic TDD configurations, almost blanksubframe (ABS) configurations, MBSFN configurations or more generally,for any subframes that for scheduling reasons, the eNB does not want touse for eMTC. For example, in TDD mode, an eNB may signal if a subframeis available for uplink, downlink or neither. In FDD, the eNB may signalif a subframe is available for uplink, downlink, both or neither.

In such cases, it might be beneficial to use different signaling schemesin TDD and FDD to minimize the signaling overhead. For example, thesubframe availability for FDD may be determined by two bitmasks, wherethe first bitmask signals the available subframes for downlink and thesecond bitmask signals the available subframes for uplink.

The subframe availability for TDD, on the other hand, may be determinedby a TDD configuration and a (single) bitmask, where the bitmask signalsif a subframe is available, and the TDD configuration signals thedirection of the subframe. If a subframe is not available (as indicatedby the mask), then that subframe may be unavailable for uplink ordownlink. If a subframe is available, then the direction of thatsubframe is given by the TDD configuration.

This type of signaling may be demonstrated by considering an examplewith the following TDD configuration:

-   -   DSUUDDSUUD        and the following bitmask to indicate subframe availability:    -   1101111110        In this case, the available downlink subframes are:    -   0,1,4,5,6 (SF9 is disabled in the mask)        as SF9 is disabled in the mask, while the available downlink        subframes are:        as SF2 is disabled in the mask. The subframe availability        bitmask may be of different lengths, depending on the particular        embodiment. For example, a bitmask may have 10 bits (signaling        every radio frame), 40 bits (signaling every 4 radio frames), or        a reduced size (e.g., assuming that subframes 0 and 5 are always        available, or assuming that paging subframes are always        available).

In some cases, a UE may take action when one or more subframes areidentified for conflicting purposes. For example, in some cases, a UEmay be configured for periodic CSI reporting, meaning certain subframesneed to be uplink for transmitting the CSI. In the event these subframesare instead scheduled for downlink transmissions, a UE may need to takeaction to resolve this conflict (or collision). In some cases, a UE maygive priority to transmitting CSI. For example, a UE may determine a setof the subframes scheduled for periodic transmission of channel stateinformation (CSI) and determine a set of subframes scheduled forphysical downlink shared channel (PDSCH) transmission. The UE may dropperiodic transmission of CSI if the set of subframes scheduled fortransmission of periodic CSI at least partially overlaps with the set ofsubframes scheduled for PDSCH transmission. In other words, receivingPDSCH may be given priority over transmission of CSI (resulting indropping of CSI transmissions).

In some cases, the eNB may signal an indication of valid downlinksubframes and an indication of subframe a different type (e.g., MBSFN orspecial subframes). Based on these indications, a UE may determine thevalidity of either the downlink subframes or the subframes of thedifferent type

FIG. 14 illustrates example operations 1400 that may be performed by aUE to determine validity of different types of subframes, based on suchindications.

The operations 1400 begin, at 1402, by determining a first set ofsubframes for valid downlink reception. At 1404, the UE determines asecond set of subframes and, at 1406, the UE determines a third set ofsubframes for valid downlink reception, based at least on the first setof subframes and the second set of subframes. At 1408, the UE receives adownlink channel in the third set of subframes for valid downlinkreception.

As an example, the second set of subframes may be MBSFN subframes. Insome cases, the UE may be configured to override the valid downlinksubframe configuration with the MBSFN subframe configuration. Forexample, the UE may receive an indication that a particular subframe isvalid (e.g., for downlink), but is also marked as MBSFN. In this case,the UE may override the valid (downlink) subframe configuration, andconsider the particular subframe to be invalid.

In some cases, a UE may be configured to set the availability ofdownlink subframes to be different for different transmission modes orchannels. For example, an eNB may configure some MBSFN subframes asvalid, in which CRS are not present. If this is the case, a UE may notbe able to receive PDSCH with CRS demodulation (e.g. transmission modes1, 2 or 6), but may be able to receive PDSCH with DMRS demodulation(e.g. transmission mode 9) and/or MPDCCH with DMRS demodulation. Thus,the subframe availability may be a function of the channel and/ortransmission mode. If a subframe is not available (e.g., due to thenon-compatibility of the channel/transmission mode with MBSFN), then theUE may skip reception in this particular subframe and count it in thetotal repetition number. Alternatively, the UE may postpone therepetition in the MBSFN subframe.

Similarly, some special subframes may be configured as valid downlinksubframes. In such a case, some transmission modes may not be availablein the special subframe. For example, transmission mode 9 may not besupported in special subframes with extended CP and 5:5:2 specialsubframe configuration. In such a case, the UE may skip reception inthis particular subframe and count it in the total repetition number.Alternatively, the UE may postpone the repetition in the specialsubframe.

In some cases, and in TDD deployments, a bundled downlink transmissionmay comprise both normal and special subframes. For some channels, theavailability of resources may be different in normal and specialsubframes. For example, following legacy LTE, a downlink control channelfor eMTC (MPDCCH) normal subframes may have 4 enhanced control channelelements (ECCEs) per RB, while some special subframes may have 2 ECCEsper RB. In this case, if a MPDCCH is repeated in the special subframe,some ECCEs may not be available for repetition. For example, a normalsubframe may have ECCEs {0,1,2,3} and a special subframe may have ECCEs{0,1}, so not all the ECCE may be repeated.

In some cases, a candidate MPDCCH spanning a number of ECCEs (e.g.{0,1,2,3}) may not be completely repeated in the special subframe (e.g.the repetition will only use {0,1}). In some other cases, there may betwo candidates for monitoring, for example candidate 1 spanning ECCEs{0,1}, and candidate 2 spanning ECCEs {2,3}. Thus, in this example, onlycandidate 1 may be repeated in the special subframe, and candidate 2 maynot be repeated in the special subframe. In this case, the eNB maytransmit DMRS in the special subframe, regardless of the candidate beingrepeated/transmitted or not.

Alternatively, the number of ECCEs per RB may be defined depending onthe number of repetitions. For example, if a UE is configured withoutMPDCCH repetition, it may receive MPDCCH in the special subframes with 2ECCEs per RB. If a UE is configured with MPDCCH repetition, then thespecial subframes may have 4 ECCE per RB such that all the candidatescan be repeated. In some other cases, the UE may treat the specialsubframe as invalid when configured with MPDCCH repetition. For example,if a UE is monitoring for an MPDCCH transmitted with repetitions, thespecial subframes with 2 ECCE per RB may be considered invalidsubframes.

As described herein, aspects of the present disclosure providetechniques that may allow eMTC UEs, hat rely on bundled transmissionsfor coverage enhancement, to contend with the fact that certainsubframes are unavailable for such bundled transmissions.

As described above, aspects of the present disclosure provide techniquesfor addressing the fact that certain subframes may not be available foruplink and/or downlink bundled transmissions.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in asoftware/firmware module executed by a processor, or in a combination ofthe two. A software/firmware module may reside in RAM memory, flashmemory, ROM memory, EPROM memory, EEPROM memory, PCM (phase changememory), registers, hard disk, a removable disk, a CD-ROM or any otherform of storage medium known in the art. An exemplary storage medium iscoupled to the processor such that the processor can read informationfrom, and/or write information to, the storage medium. In thealternative, the storage medium may be integral to the processor. Theprocessor and the storage medium may reside in an ASIC. The ASIC mayreside in a user terminal. In the alternative, the processor and thestorage medium may reside as discrete components in a user terminal.Generally, where there are operations illustrated in Figures, thoseoperations may have corresponding counterpart means-plus-functioncomponents with similar numbering.

In one or more exemplary designs, the functions described may beimplemented in hardware, software/firmware or combinations thereof. Ifimplemented in software/firmware, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by ageneral purpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software/firmware is transmitted from awebsite, server, or other remote source using a coaxial cable, fiberoptic cable, twisted pair, digital subscriber line (DSL), or wirelesstechnologies such as infrared, radio, and microwave, then the coaxialcable, fiber optic cable, twisted pair, DSL, or wireless technologiessuch as infrared, radio, and microwave are included in the definition ofmedium. Disk and disc, as used herein, includes compact disc (CD), laserdisc, optical disc, digital versatile disc (DVD), floppy disk andBlu-ray disc where disks usually reproduce data magnetically, whilediscs reproduce data optically with lasers. Combinations of the aboveshould also be included within the scope of computer-readable media.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein, but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method for wireless communications by a userequipment (UE), comprising: identifying one or more subframes, within atleast one radio frame, unavailable for bundled transmissions acrossmultiple subframes, wherein the one or more subframes unavailable forbundled transmissions comprise a first group comprising subframes thatare determined not available for bundled transmissions to any UE thatcommunicates using a narrowband region and a second group comprisingsubframes that are determined not available for bundled transmissions toone or more particular UEs; and communicating, via the narrowbandregion, using bundled transmissions across multiple subframes based onthe identification.
 2. The method of claim 1, wherein the communicatingcomprises: skipping bundled transmissions that would occur on one ormore unavailable subframes of the second group; or postponing bundledtransmissions if they are scheduled to occur on one or more unavailablesubframes of the first group and scheduling the postponed bundledtransmissions to one or more later occurring subframes.
 3. The method ofclaim 1, wherein the identification is based, at least in part, ondynamically scheduled subframe configurations.
 4. The method of claim 3,further comprising receiving signaling indicating at least one of:availability of subframes for bundled uplink transmissions oravailability of subframes for bundled downlink transmissions.
 5. Themethod of claim 4, wherein the signaling is provided via one or morebitmaps.
 6. The method of claim 4, wherein the signaling is providedvia: a first subframe configuration for determining availability ofsubframes for bundled downlink transmissions; and a second subframeconfiguration for determining availability of subframes for bundleduplink transmissions.
 7. The method of claim 6, further comprising:determining whether or not the UE is in a coverage enhancement (CE)mode; and transmitting using a subsequent subframe based on thedetermination.
 8. The method of claim 6, further comprising: receiving agrant indicating a subsequent subframe is available for uplinktransmission; and for at least a current radio frame, transmitting usingthe subsequent subframe and subframes indicated as available based onthe second subframe configuration.
 9. The method of claim 1, wherein theidentification is based, at least in part on a type of channel subjectto bundled transmission.
 10. The method of claim 9, wherein: theidentification is based on a first reference subframe configuration fora first set of one or more channel types; and the identification isbased on a second reference subframe configuration for a second set ofone or more channel types.
 11. The method of claim 1, wherein the UEreceives system information (SI) updates regarding subframeconfigurations with a different periodicity than UEs that do notcommunicate via the narrowband region.
 12. An apparatus for wirelesscommunications, comprising: at least one processor configured toidentify one or more subframes, within at least one radio frame,unavailable for bundled transmissions across multiple subframes, whereinthe one or more subframes unavailable for bundled transmissions comprisea first group comprising subframes that are determined not available forbundled transmissions to any UE that communicates using a narrowbandregion and a second group comprising subframes that are determined notavailable for bundled transmissions to one or more particular UEs; andan interface configured to communicate, via the narrowband region, usingbundled transmissions across multiple subframes based on theidentification.
 13. The apparatus of claim 12, wherein the communicationis adjusted to: skip bundled transmissions that would occur on one ormore unavailable subframes of the second group; or postpone bundledtransmissions if they are scheduled to occur on one or more unavailablesubframes of the first group and to schedule the postponed bundledtransmissions to one or more later occurring subframes.
 14. Theapparatus of claim 12, wherein the identification is based, at least inpart, on dynamically scheduled subframe configurations.
 15. Theapparatus of claim 14, wherein the interface is configured to receivesignaling indicating at least one of: availability of subframes forbundled uplink transmissions or availability of subframes for bundleddownlink transmissions.
 16. The apparatus of claim 15, wherein thesignaling is provided via one or more bitmaps.
 17. The apparatus ofclaim 15, wherein the signaling is provided via: a first subframeconfiguration for determining availability of subframes for bundleddownlink transmissions; and a second subframe configuration fordetermining availability of subframes for bundled uplink transmissions.18. The apparatus of claim 17, wherein: the at least one processor isfurther configured to determine whether or not the UE is in a coverageenhancement (CE) mode; and the interface is configured to communicateusing a subsequent subframe based on the determination.
 19. Theapparatus of claim 17, wherein: the interface is configured to receive agrant indicating a subsequent subframe is available for uplinktransmission; and the interface is configured, for at least a currentradio frame, to communicate using the subsequent subframe and subframesindicated as available based on the second subframe configuration. 20.The apparatus of claim 12, wherein the identification is based, at leastin part on a type of channel subject to bundled transmission.
 21. Theapparatus of claim 20, wherein: the identification is based on a firstreference subframe configuration for a first set of one or more channeltypes; and the identification is based on a second reference subframeconfiguration for a second set of one or more channel types.
 22. Anapparatus for wireless communications, comprising: means for identifyingone or more subframes, within at least one radio frame, unavailable forbundled transmissions across multiple subframes, wherein the one or moresubframes unavailable for bundled transmissions comprise a first groupcomprising subframes that are determined not available for bundledtransmissions to any UE that communicates using a narrowband region anda second group comprising subframes that are determined not availablefor bundled transmissions to one or more particular UEs; and means forcommunicating, via the narrowband region, using bundled transmissionsacross multiple subframes based on the identification.
 23. The apparatusof claim 22, wherein the means for communicating comprises: means forskipping bundled transmissions that would occur on one or moreunavailable subframes of the second group; or means for postponingbundled transmissions if they are scheduled to occur on one or moreunavailable subframes of the first group and scheduling the postponedbundled transmissions to one or more later occurring subframes.
 24. Theapparatus of claim 22, wherein the identification is based, at least inpart on a type of channel subject to bundled transmission.
 25. Theapparatus of claim 24, wherein: the identification is based on a firstreference subframe configuration for a first set of one or more channeltypes; and the identification is based on a second reference subframeconfiguration for a second set of one or more channel types.
 26. Anon-transitory computer-readable medium encoded with instructions thatwhen executed, cause a user equipment (UE) to: identify one or moresubframes, within at least one radio frame, unavailable for bundledtransmissions across multiple subframes, wherein the one or moresubframes unavailable for bundled transmissions comprise a first groupcomprising subframes that are determined not available for bundledtransmissions to any UE that communicates using a narrowband region anda second group comprising subframes that are determined not availablefor bundled transmissions to one or more particular UEs; andcommunicate, via the narrowband region, using bundled transmissionsacross multiple subframes based on the identification.
 27. Thenon-transitory computer-readable medium of claim 26, wherein thecomputer- readable medium is further encoded to: skip bundledtransmissions that would occur on one or more unavailable subframes ofthe second group; or postpone bundled transmissions if they arescheduled to occur on one or more unavailable subframes of the firstgroup and scheduling the postponed bundled transmissions to one or morelater occurring subframes.
 28. The non-transitory computer-readablemedium of claim 26, wherein the identification is based, at least inpart on a type of channel subject to bundled transmission.
 29. Thenon-transitory computer-readable medium of claim 28, wherein: theidentification is based on a first reference subframe configuration fora first set of one or more channel types; and the identification isbased on a second reference subframe configuration for a second set ofone or more channel types.